Preheat the oven to 375 degrees F.

Grease 24 (1/2 cup) mini bundt pans. (2 pans of 12 mini bundt tins). In an electric mixer, fitted with a paddle attachment, combine the butter and sugar. Beat until smooth.

Add the eggs one at a time, and continue to beat until incorporated. Add the orange zest and vanilla. Add the flour and salt, 1/2 cup at a time until the batter is smooth. Divide the batter equally into the prepared pans. Bake for 20 to 25 minutes for the mini loaves and 45 minutes for the regular size loaves or until the top of the cakes dome and are slightly golden. Remove from the oven and cool slightly. Unmold the cakes onto wire racks.

In a small mixing bowl, combine the confectioners' sugar and orange juice together. Whisk until smooth. Place the wire racks over a baking sheet, lined with parchment paper. Drizzle the glaze over each cake. Cool the cakes to room temperature. Place the cakes on a serving platter and serve.